Inverse analysis of pipe viscoelastic parameters using frequency-domain transient-based method

The effectiveness of the transient modeling in viscoelastic pipes mainly depends on the accuracy of the used Kelvin-Voigt (K-V) model, and the viscoelastic parameters of the K-V model are usually obtained by data-based inverse analysis (pre-calibration) for the focused pipe system. Currently, the inverse analysis for such parameter identification is usually based on the time-domain pressure signal calibration, which is very time-consuming and easily affected by other factors in the system such as skin friction and unsteady turbulence. This paper aims to develop a frequency-domain transient-based method (FDTBM) to efficient and accurate identification of viscoelastic parameters for transient modeling and analysis in viscoelastic pipes. To this end, the transient frequency response is firstly derived by the transfer matrix method for viscoelastic pipeline flow systems. The influence of the pipe-wall viscoelasticity on the transient frequency shift is then examined and applied to inversely identify the viscoelastic parameters. The developed method is then validated through various numerical applications, and the results show that this FDTBM is able to efficiently identify viscoelastic parameters of different pipe systems. A systematic analysis is further conducted to understand and determine the dependence of the identification accuracy of the developed FDTBM on different dimensionless parameters in viscoelastic pipe systems. Finally, the main results and findings of this study are summarized in the end of the paper.